The use of mobile communications networks has substantially increased over the last decade. To meet user demand for mobile communications networks, mobile communications network operators have increased the number of base stations and/or base transceiver stations (BTS). Thus, mobile communications networks operators hope to reduce the costs associated with installing and operating the base stations while meeting increased user demand for mobile communication networks.
FIG. 1 is a diagram illustrating a system structure of a radio access network (RAN) 10 in relevant art. Specifically, the system architecture of the RAN 10 adopts a distributed base band units (BBUs) with fixed point-to-point transmission, which can be widely found in the current 4G LTE (long term evolution) network. In FIG. 1, the solid connection lines indicate physical network connections (which may be wired or wireless), while the dashed connection lines represent software interfaces (and the corresponding hardware implementations thereof).
The exemplary RAN 10 comprises a remote radio head (RRH) pool 11 communicatively connected to a distributed BBU 12 through a fixed point to point link, which may use the Common Public Radio Interface (CPRI) standard, the Open Base Station Architecture Initiative (OBSAI) standard, or other suitable fronthaul communication standards and suitable combinations thereof.
The RRH pool 11 comprises a plurality of remote radio heads (e.g., RRHs 110a, 110b, 110c), which may be physically and functionally identical remote radio transceiver units. A remote radio head generally comprises components that include power supply, transceiver, amplifier (power amplifier and/or low-noise amplifier), and duplex filter. The remote radio head is usually installed close to an antenna, or the remote radio head may be structurally integrated with the actual antenna, resulting in an active antenna. As used in this disclosure, the term remote radio head refers to both, a separate remote radio head and a radio head integrated into the active antenna. The RRHs 110 in the RRH pool 11 are at least partially interconnected through network connection.
The distributed BBU 12 comprises a base band unit pool that includes a plurality of base band units (BBUs) 121a, 121b, 121c, an Operation Support System (OSS) 122, and an Element Management System (EMS) 123. The base band units 121a, 121b, 121c are controllably coupled to the EMS 123 through connections that implements suitable software interfaces. The EMS 123 is controllably coupled to the OSS through suitable hardware/software interfaces.
The distributed BBU 12 directly exercises control and resource management over the RRH pool 11. For example, each of the BBUs 121a, 121b, and 121c is connected to a respective RRH (e.g., 110a/110b/110c) in the RRH pool 11 through fixed point-to-point connection.
The distributed BBU 12 is generally situated, operated, and maintained on a mobile network operator (MNO) premises. This kind of RAN often needs an operator to manually set up RRH, fixed links, and BBU configurations, and is generally incapable of re-configuring network resource parameters automatically and/or dynamically to meet different network service requirements. In addition, The MNO of the RAN10 is required to maintain and expand both the sizable RRH equipment (e.g., the RRH pool 11) and the corresponding distributed BBU 12 to fulfill the increasing demand for wireless service. The fixed connection arrangement between the RRH pool 11 and the distributed BBU 12 offers little flexibility, and provides little options for the operators of the mobile communications networks in terms of cost reduction. Moreover, the fixed deployment of the RAN 10 offers little operational flexibility, as such arrangement is often optimized for certain application circumstances, e.g., to fulfill the capacity requirement for a certain peak time and a location, thus may cause over-provision of resource capacity for the rest of the time.